KnowledgeBase 00061: Moving the Two Digit Year Number Range

Multivalue database products have always adopted a convention that a two digit
year number represents a date in the range 1930 to 2029, a range that is
roughly centred on the point at which the data model was created. We are
rapidly approaching the upper limit of this range and the time has come to
consider changing how two digit year numbers are interpretted.

The YEARBASE Configuration Parameter

In common with many other multivalue products, QM provides a way to move
the 100 year range adopted for two digit year numbers. In QM, this is done by
setting the YEARBASE configuration parameter to the start year of the range.
This parameter defaults to 1930 for compatibility with other products.

YEARBASE is a private configuration parameter that takes its initial value
from the QM configuration file but is maintained separately for each active
QM session and can be modified with, for example,

CONFIG YEARBASE 1970

Application Issues

It is strongly recommended that any application that allows entry of dates
with two digit year numbers should reflect these back onto the screen with all
four digits so that the user can see any possible unwanted effects of applying
the 100 year range.